The bot was based on a pre-trained neural network – More information on the netwrok can be found here.

After thousands of images and thousands of comments involving questions, compliments and insults, we decided to gather all the information on ColorizeBot’s interactions, and share some of our thoughts and statistics. If you browsed here because you are interested in some statistics, roll down to the second part of this post…

…Overall it seems the bot does quite an amazing job. We must remember the coloring algorithm was trained using ImageNet, which is a set of 80000+ images. The images were transformed to B&W and then the program was trained to paint them back to the original color comparing its results to the original colors

Since all the photos on ImageNet are high quality photos, the algorithm works best with similar photos.